Study: How our brain processes present dangers, past experiences

Study: How our brain processes present dangers, past experiences
Image by skeeze from Pixabay

A new study shows how our brain processes present dangers and past experiences, shedding light on post-traumatic stress disorder (PTSD).

The study, which was published in the journal Nature, investigated the neurological processes present in mice when it comes to distinguishing real and present dangers from those linked to past experiences.

The findings are considered useful in understanding PTSD, which refers to one’s inability to identify between past and present dangers or to acknowledge “safe” situations.

“Memories of a traumatic episode can last for a long time,” says senior author Eric Klann, director of New York University’s Center for Neural Science.

“But we are able to use such memories selectively: to predict and respond to a subsequent, related danger while also recognizing when threats do not exist. This is especially important for survival behavior in an uncertain environment such as a conflict zone or at times of social unrest,” he added.

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“This has significant implications for memory disorders such as PTSD, where patients have difficulty distinguishing between safety and threat cues,” says lead author Prerana Shrestha, a postdoctoral researcher in the Center for Neural Science.

According to the researchers, determining and properly responding to cues in an uncertain field can impact animal survival. This particularly applies to cues that warn of danger, which lead to behaviors such as freezing in order to avoid detection. However, an uncertain environment can produce cues that predict a lack of danger or safety.

Animals are expected to respond to the cue by being defensive and to safety cues by preventing a threat response and showing normal behaviors.

The scientists aimed to pinpoint the cellular molecules for long-term storage of threat and safety-cue-associated memories.

Brain on pain

Not all memories and experiences are positive. In another study, scientists found that a small area of the brain can control one’s sense of pain. Sixteen brain centers receive inhibitory input from the CeAga.

Researchers from Duke University identified a small area of the brain in mice that can deeply control the sense of pain in the animals.

This part of the brain is found in the amygdala, which is considered the source of negative emotions and responses.

“People do believe there is a central place to relieve pain, that’s why placebos work,” said senior author Fan Wang, the Morris N. Broad Distinguished Professor of neurobiology in the School of Medicine. “The question is where in the brain is the center that can turn off pain.”

“Most of the previous studies have focused on which regions are turned ON by pain,” Wang said. “But there are so many regions processing pain, you’d have to turn them all off to stop the pain. Whereas this one center can turn off the pain by itself.”

Published in Nature Neuroscience, the study “General anesthetics activate a potent central pain-suppression circuit in the amygdala” highlighted the role of general anesthesia in activating a specific subset of inhibitory neurons in the central amygdala, which were labeled as the CeAga neurons. CeA refers to central amygdala; ga hints activation by general anesthesia.

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